1. Field Of The Invention
The present invention relates to technology for distributing video and/or audio content from a server apparatus via a relay apparatus to a telephone.
2. Description Of The Related Art
Services for distributing video and/or audio content to mobile phones by streaming have been proposed (see JP 2003-037836A, for example). “Streaming” means distribution in which the mobile phone serving as the client can reproduce the content simultaneously while receiving it. The advantage of streaming is that the user does not have to wait until the download of the whole content is finished since the client reproduces a part of the content that has already been received while receiving subsequent parts of the content.
In services that are already implemented, streaming content distribution is accomplished by the following procedure.
In FIG. 13, a mobile phone 1b that is part of a mobile phone network 1a can realize a videophone function by using a videophone protocol. By operating the mobile phone 1b, the user first enters a telephone number that is assigned to a relay apparatus 1c and then enters a character string of several digits to specify the content. This character string is referred to as a “sub-address”. This sub-address is stored in advance in the relay apparatus 1c in association with a content ID. In the example shown in FIG. 13, the content to which the content ID “C0001” has been assigned is specified by the sub-address “90001.”
Now let us examine the case that a call-connection signal including, for example, the number “*8608*90001” is sent from the mobile phone 1b. In this number “*8608*90001”, the initial “*” is a predetermined prefix, and the following “8608” is a shortened telephone number referred to as “special number”. The following “*” is referred to as a separator, and the final “90001” is the sub-address. Based on the telephone number (special number) “8608” sent from the mobile phone 1b, a telephone connection between the mobile phone 1b and the relay apparatus 1c is established, and the sub-address “90001” is notified to the relay apparatus 1c. The content ID “C0001” corresponding to the sub-address “90001” that has been notified to the relay apparatus 1c is notified to a CP server apparatus 1d, and the content corresponding to this ID is obtained from the CP server apparatus 1d. Then, the relay apparatus 1c sends the obtained content by videophone protocol to the mobile phone 1b. When the mobile phone 1b receives the content, it successively reproduces the content.
The above-noted correspondence between the sub-address and the content ID is set in advance by the content provider, who manages the CP server apparatus 1d, and the network provider, who manages the mobile phone network 1a and the relay apparatus 1c. That is to say, since the correspondence between the sub-address and the content ID is fixed through an agreement between those two parties, when the number of content items increases due to an increase in the number of content providers, then the number of sub-addresses has to be increased by the same amount. In the example in FIG. 13 for example, only a four-digit numeric string “xxxx” (where x is an arbitrary numeral) is provided as a valid address in the five-digit sub-address “9xxx”, so that the number of content items that can be designated with this system of sub-addresses is limited to 9999 at the most.
Consequently, if the number of content items is increased beyond that, then this must be accommodated by increasing the number of digits of the sub-address or by making the configuration of the sub-address more complicated. However, the operation burden on the user is smaller if the sub-address is a simple character string that is as short as possible, so that there is a need for way to accommodate an increase in the number of content items without increasing the number of digits of the sub-address and without making the configuration of the sub-address more complicated.